Add commented out logic for SPSR repository

Not adding the submodule yet - need to be sure this can actually work -
but looking to use the "header only" mode of SPSR added to upstream code
to replace the bundled copy in BRL-CAD.

Once it is demonstrated to be working, add the submodule and uncomment
in dependencies.cmake

CMake/FindPOISSONRECON.cmake

@@ -0,0 +1,40 @@
+# Find Adaptive Multigrid Solver headers for Poisson Surface Reconstruction
+#
+# Once done this will define
+#
+#  POISSONRECON_FOUND - system has Adaptive Multigrid Solver headers
+#  POISSONRECON_INCLUDE_DIR - the Adaptive Multigrid Solver include directory
+#
+# and the following imported target:
+#
+#  POISSONRECON::POISSONRECON- Provides include dir for headers
+
+set(_POISSONRECON_SEARCHES)
+
+# Search POISSONRECON_ROOT first if it is set.
+if(POISSONRECON_ROOT)
+  set(_POISSONRECON_SEARCH_ROOT PATHS ${POISSONRECON_ROOT} NO_DEFAULT_PATH)
+  list(APPEND _POISSONRECON_SEARCHES _POISSONRECON_SEARCH_ROOT)
+endif()
+
+# Try each search configuration.
+foreach(search ${_POISSONRECON_SEARCHES})
+	find_path(POISSONRECON_INCLUDE_DIR NAMES SPSR/Reconstructors.h ${${search}} PATH_SUFFIXES include)
+endforeach()
+
+mark_as_advanced(POISSONRECON_INCLUDE_DIR)
+
+# handle the QUIETLY and REQUIRED arguments and set ZLIB_FOUND to TRUE if
+# all listed variables are TRUE
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(POISSONRECON REQUIRED_VARS POISSONRECON_INCLUDE_DIR)
+
+if(POISSONRECON_FOUND)
+    set(POISSONRECON_INCLUDE_DIRS ${POISSONRECON_INCLUDE_DIR})
+
+    if(NOT TARGET POISSONRECON::POISSONRECON)
+      add_library(POISSONRECON::POISSONRECON UNKNOWN IMPORTED)
+      set_target_properties(POISSONRECON::POISSONRECON PROPERTIES
+        INTERFACE_INCLUDE_DIRECTORIES "${POISSONRECON_INCLUDE_DIRS}")
+    endif()
+endif()

dependencies.cmake

@@ -231,6 +231,9 @@ add_project(opencv GROUPS "BRLCAD_EXTRA")
 # https://github.com/davideberly/GeometricTools
 add_project(gte GROUPS "BRLCAD")
 
+# Adaptive Multigrid Solvers - Poisson Surface Reconstruction code.
+# https://github.com/mkazhdan/PoissonRecon
+#add_project(poissonrecon GROUPS "BRLCAD")
 
 # OpenMesh Library - library for representing and manipulating polygonal meshes
 # https://www.graphics.rwth-aachen.de/software/openmesh/

poissonrecon/CMakeLists.txt

@@ -0,0 +1,53 @@
+# Decide if we're using GeometricTools
+cad_enable(POISSONRECON "libbg")
+
+unset(POISSONRECON_BUNDLED CACHE)
+
+if (NOT ENABLE_POISSONRECON AND NOT DISABLE_POISSONRECON)
+
+  # https://github.com/mkazhdan/PoissonRecon/
+  find_package(POISSONRECON)
+
+  if (NOT TARGET POISSONRECON::POISSONRECON)
+    set(ENABLE_POISSONRECON "ON" CACHE BOOL "Enable SPSR build")
+  endif (NOT TARGET POISSONRECON::POISSONRECON)
+
+endif (NOT ENABLE_POISSONRECON AND NOT DISABLE_POISSONRECON)
+
+set(ENABLE_POISSONRECON "${ENABLE_POISSONRECON}" CACHE BOOL "Enable SPSR build")
+
+# Decision made
+
+if (ENABLE_POISSONRECON)
+
+  git_submodule_init(PoissonRecon POISSONRECON/CMakeLists.txt)
+
+  TargetDeps(POISSONRECON)
+
+  ExternalProject_Add(POISSONRECON_BLD
+    URL "${CMAKE_CURRENT_SOURCE_DIR}/PoissonRecon"
+    BUILD_ALWAYS ${EXT_BUILD_ALWAYS} ${LOG_OPTS}
+    PATCH_COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/poissonrecon.patch
+    CMAKE_ARGS
+    ${BUILD_TYPE_SPECIFIER}
+    -DCMAKE_INSTALL_PREFIX=${CMAKE_NOBUNDLE_INSTALL_PREFIX}
+    LOG_CONFIGURE ${EXT_BUILD_QUIET}
+    LOG_BUILD ${EXT_BUILD_QUIET}
+    LOG_INSTALL ${EXT_BUILD_QUIET}
+    LOG_OUTPUT_ON_FAILURE ${EXT_BUILD_QUIET}
+    STEP_TARGETS install
+    )
+
+  TargetInstallDeps(POISSONRECON POISSONRECON_DEPENDS)
+
+  set(POISSONRECON_BUNDLED TRUE CACHE BOOL "SPSR bundle flag")
+
+endif (ENABLE_POISSONRECON)
+
+# Local Variables:
+# tab-width: 8
+# mode: cmake
+# indent-tabs-mode: t
+# End:
+# ex: shiftwidth=2 tabstop=8
+

poissonrecon/poissonrecon.deps

@@ -0,0 +1,2 @@
+PATCH
+

poissonrecon/poissonrecon.patch

@@ -0,0 +1,23 @@
+diff -Naur PoissonRecon/CMakeLists.txt POISSONRECON_BLD/CMakeLists.txt
+--- PoissonRecon/CMakeLists.txt	1969-12-31 19:00:00.000000000 -0500
++++ POISSONRECON_BLD/CMakeLists.txt	2024-07-31 16:48:17.163077007 -0400
+@@ -0,0 +1,19 @@
++cmake_minimum_required(VERSION 3.8)
++
++project(SPSR)
++
++file(GLOB SPSR_FILES "${CMAKE_SOURCE_DIR}/Src/*")
++
++if(NOT DEFINED INCLUDE_DIR)
++  set(INCLUDE_DIR include)
++endif(NOT DEFINED INCLUDE_DIR)
++
++install(FILES ${SPSR_FILES} DESTINATION ${INCLUDE_DIR}/SPSR)
++
++# Local Variables:
++# tab-width: 8
++# mode: cmake
++# indent-tabs-mode: t
++# End:
++# ex: shiftwidth=2 tabstop=8
++